I'm not 100% sure, but I think you might need to get the computer system reset, I believe with Airbag systems, once they fire, the computer logs the info and must be reset once the repair is complete, usually by a qualified tech, airbag systems are not intended to be a DIY job. Not saying they can't be, but because of the potential for injury for incorrect installation.

Just go to a Ford dealer and ask what is involved in replacing the airbag system after an accident, tell them you are trying to get an idea on whether the car is worth putting the repairs into.